Sensory and stimulatory prosthetic devices to treat spinal cord injuries and other nervous system diseases require implantation of electrically conductive interfaces between neural tissues and microelectrodes. Currently available metal/silicon-based devices are not stable over the long term, mostly due to gliosis and inflammation. This interdisciplinary R01 project focuses on the design of a novel class of nanomaterials for neurobiological applications based on carbon nanotube fibers (CNF). Fabricated from single wall carbon nanotubes (SWNT) with a polymer binder in the form of flexible "hair-like" fibers, CNF combine unique properties of porous nanostructured scaffolds, conductive microwires and electrodes, permeable microfluidic conduits, and high area supports for bioactive agents and biocatalysts. Based on our preliminary results and analysis of published data, we anticipate that CNF can be modified to provide an intimate nerve cell adhesive substrate with increased conductivity and with reduced affinity for glial cells. CNF can be formed into a bundle of individually addressable fibers/wires connected to an external chip or computer controller for specific stimulation/recording of neural activity. A multidisciplinary team of nanotechnology, biomaterials and neurobiological scientists will: 1) optimize fabrication of functionalized CNF for neural implants and electrodes;2) perform surface modification and test CNF with respect to biocompatibility with neural and glial cells in vitro;3) assess electrophysiological features of CNF ex vivo and demonstrate long term compatibility and integration of CNF in the central nervous system in vivo. Our central aim is to demonstrate that suitably modified and functionalized CNF can provide a unique environment for neural tissue engineering and, especially, for generating chronically implantable interfaces. In the short term, our research program will yield a new biocompatible platform for chronic neuroprosthetic implants and electrodes. In the long term, we will elaborate a strategy to design "artificial axons" from functionalized SWCN nanocomposite fibers. The success of the proposed project will have a broad impact on the progress of clinical implantable neural devices for monitoring and facilitation of neural activity and growth, and, ultimately, for reconnecting brain signal pathways after neural injury and repairing damage to the nervous system.